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MWRA posts results from tests for coronavirus in wastewater; peak seen in spring and low point in late June

Results for traces of the coronavirus at the Deer Island wastewater treatment plant up to July 16. The MWRA system is divided into two regions, north and south.MWRA

Here’s another indicator to keep your eye on, if you’re concerned about the deadly coronavirus making a comeback in Massachusetts.

The Massachusetts Water Resources Authority has begun posting on its website the results of testing for the coronavirus in wastewater at the Deer Island treatment plant.

The results show traces of the virus, SARS-CoV-2, peaking in the spring, then dropping and hitting a low around late June. The numbers then edge up slightly in the first weeks of July.

MWRA spokeswoman Ria Convery said in a statement that “it did appear that the signal was increasing slightly from the last week in June into the first few days of July. However, the data since early July has remained relatively flat.”


Samples are currently being taken 3 times a week, the MWRA said on its website. The results currently posted reflect tests up to July 16.

The data are shared with staff from the Department of Public Health, the Department of Environmental Protection, the Executive Office of Health and Human Services, and the Executive Office of Energy and Environmental Affairs, the website said.

“It is important to note that this is a pilot of an evolving science. The results from this study will be used by public health officials as an additional tool for the Commonwealth to track how the pandemic is trending in Massachusetts, along with data from clinical tests, hospitalizations, etc.,” the website said.

The innovative testing comes as Massachusetts, after a harrowing spring, appears to be keeping the virus at relatively low levels, even as the pandemic is flaring up in other parts of the United States. With the economy gradually restarting and the school year looming, Massachusetts officials say they’re staying vigilant for any resurgence of the virus, and they’re urging people to continue to wear face coverings, to socially distance, to wash their hands, and disinfect surfaces.


The authority’s board of directors last month approved the award of a $200,000 contract with Somerville-based Biobot Analytics Inc. for a six-month pilot study, the authority said. Biobot had conducted an initial study at the plant in early March.

MWRA has said it will likely use the lessons learned from the pilot to establish a long-term program.

The Deer Island treatment plant, a landmark featuring giant egg-shaped “digesters” at the edge of Boston Harbor, treats wastewater from Boston and 42 other communities in Eastern Massachusetts before sending it out through a 9.5-mile-long tunnel into Massachusetts Bay.

Biobot is now working with about 400 facilities in 42 states across the US, which represents over 10% of the US population, the company has said.

In an opinion piece recently published in STAT, a group of experts called for a national wastewater testing program. The authors, who included Dr. Ashish Jha, head of the Harvard Global Health Institute, wrote that “we need new tools for understanding Covid-19 transmission. A national wastewater surveillance program offers a cost-effective approach to track Covid-19 across the majority of the U.S. population and provide early warnings of resurgence.”

STAT reported in May that the intriguing idea of testing wastewater had “quickly leapt to the threshold of real-world use.”

Massachusetts as of Sunday had tallied 8,310 confirmed-case deaths plus another 219 probable deaths. About a dozen people a day are still dying of confirmed cases of the coronavirus, according to state data as of last week. The closely-watched University of Washington Institute for Health Metrics and Evaluation model predicts the state could see the death toll rise to nearly 10,000 by Nov. 1.


Martin Finucane can be reached at